The invention is based on a hand power tool, in particular a drill hammer and/or jackhammer.
Known hand power tools of this kind are provided by the safety coupling, which is intended to protect the operator against an excessively great reaction torque if the tool being driven stops suddenly, for instance if a drilling tool seizes. In a known hand power tool, a safety coupling of this kind is provided in the region of the rotary sleeve, which is adjacent to the tool receptacle. The rotary sleeve is designed in two parts. On the end toward the drive mechanism, the sleeve part that receives the hammering mechanism receives a coupling sleeve inserted into it on the power takeoff end. The drive moment is transmitted by means of a plurality of transmission elements, in the form of balls, located in through bores of the rotary sleeve part. They are retained radially inward in approximately V-shaped ball pockets of the coupling sleeve and are retained outward by a spring-loaded wedge-shaped support ring. If a predetermined limit torque is exceeded, the transmission elements are forced radially out of the V-shaped ball pockets of the coupling sleeve, so that with the coupling sleeve blocked, the rotary sleeve part that receives it and is still being driven as before can continue to revolve, and a relative motion between the two is possible. The spring-loaded support ring makes the axial compensatory motion possible. This two-part design is comparatively expensive, since both the rotary sleeve part and the coupling sleeve have to be ground on both the outside and the inside. Since the tool receptacle must be accommodated near the striking pin of the hammering mechanism, and the smaller-diameter coupling sleeve, problems arise in terms of bracing, sealing and damping in the region of the striking pin of the hammering mechanism. Moreover, the play that exists between the coupling sleeve and the rotary sleeve impairs the concentricity of a tool fastened in place when it is driven to rotate.